The driving mechanism of a conventional labeling machine, referring to FIG. 1, has a transmission assembly 4a consisting of a plurality of pulleys 42a coupled with a plurality of linking bars 41a and belts 44a, and axles 46a with an adjustable width to mate a center guide post holding label films of varying dimensions.
The conventional labeling machine also has a linking belt 48a to link a driving wheel 40a and a linking pulley 43a. A pulley shaft 421a is provided to connect to pulleys 42a on the linking bars 41a. The pulleys 42a at two ends of the linking bar 41a are transmitted by the belts 44a. The pulleys 42a on the neighboring linking bars 41a are coupled on the pulley shaft 421a. Thus the linking bars 41a and the belts 44a are linked in a selected order. During repair and maintenance, the belts 44a cannot be removed and displaced individually. All the belts 44a at the front end and rear end have to be disassembled, then assembled and installed again in the selected order. It takes a great deal of time. Moreover, the belts 44a between the linking bars 41a of the transmission assembly 4a have to be wound in a staggered manner to prevent mutual friction. Hence a greater space is required. In addition, the space needed to adjust the tension of the numerous belts 44a is limited, the tension of the belts 44a vary, transmission speed is uneven and transmission quality is affected. Furthermore, the adjustment mechanism comprising the linking bars 41a can only be anchored on the linking pulley 43a and the axle 46a, and the rest linking bars 41a mounted on the pulley shaft 421a are suspended. Hence shaking frequently occurs on the linking bars 41a that further impacts transmission effect of the belts 44a. This results in a shortened life span of the elements. There are still rooms for improvement.
In short, the driving mechanism of the conventional labeling machine still has many drawbacks in practice, notably:
1. A greater number of belts are needed. Replacement of the belts is tedious and wastes a lot of manpower and time.
2. The transmission elements occupy a great deal of space and result in difficult space configuration.
3. The belts are numerous and their tension is difficult to control, and result in uneven speed.
4. The transmission elements have many moving hinges. Shaking takes place and steadiness suffers.